[SPLIT] Let P=12+50ln x give percent of email which is spam.

[almars06]

Suppose tha the function P=12+50ln x represents the percentage of inbound email in the U.S. that is considered spam, where x is the number of years after 2001. Calculate the spam in the year 2005. This part I have solved but the second part is confusing. I'm not sure where to start.

Use this model to approximate the year that the percent of spam will reach 90% provided that law enforcement regarding spammers does not change?

 

[stapel]

Plug the given percentage value into to variable which stands for "percent", and solve for the value of the variable which stands for "years after 2001". Then add this value to 2001 to find the year.

Eliz.

 

[almars06]

I have already gotten the answer for the 2001 and 2005 deal. What I can't figure out where to start is the 90% part of the question which is the last sentence in the last reply.

 

[o_O]

Show us your work and we'll help you locate any errors. For that question, you're given P = 90. Then solve for x. This may prove to be useful:
\(\displaystyle lnx = log_{e}x\)

and

\(\displaystyle log_{a}b = c\) also means \(\displaystyle a^{c} = b\)

 

[stapel]

I have already gotten the answer for the 2001 and 2005 deal.

So you've figured out what the "x" stands for, plugged in x-values, done the computations, and have interpreted the decimal/percentage answers. So you know what "P" stands for.

What I can't figure out where to start is the 90% part of the question which is the last sentence in the last reply.

They give you a percentage. What does "P" stand for? So where should the percentage be plugged in?

They asked for the time. What does "x" stand for? So what should you solve for?

Eliz.

 

[almars06]

Thanks all for your comments. I get it!